Alternating current generators
分类：轮机英语小册子
Alternating current generators
A coil of wire rotating in a magnetic field produces a current.
The power factor is a measure of the phase difference between voltage and current and is expressed as the cosine of the phase angle.
An automatic voltage regulator (AVR) consists basically of a circuit fed from the alternator output voltage which detects small changes in voltage and feeds a signal to an amplifier which changes teh excitation to correct the voltage.
Three phases alternators arranged for paralled operation require a considerable amount of instrumentations.
This will include ammeters, wattmeter, voltameter, frequency meter and a synchronizing device.